Conventionally, a photopolymerizable composition using a squarylium compound as a sensitizing dye has been known.
Japanese Published Unexamined Patent Application No.48665/1990 discloses a photopolymerizable composition in which a squarylium compound is used as a sensitizing dye and s-triazine is used as a radical generator.
Also, Japanese Published Unexamined Patent Application No.142346/1988 discloses a photopolymerizable composition in which a squarylium compound is used as a sensitizing dye and an adinium salt is used as a radical generator.
Further, Japanese Published Unexamined Patent Application No.17525/1993 discloses a photopolymerizable composition in which a squarylium compound is used as a sensitizing dye and a metal-arene complex is used as a radical generator.